In general how does the environment aid in the survival of organisms?

The chemical evolution from self-catalytic chemical reactions to life (see Origin of life) is not a part of biological evolution, but it is unclear at which point such increasingly complex sets of reactions became what we would consider, today, to be living organisms.

Precambrian stromatolites in the Siyeh Formation, Glacier National Park. In 2002, William Schopf of UCLA published a controversial paper in the journal Nature arguing that formations such as this possess 3.5 billion year old fossilized algae microbes. If true, they would be the earliest known life on earth.Not much is known about the earliest developments in life. However, all existing organisms share certain traits, including cellular structure and genetic code. Most scientists interpret this to mean all existing organisms share a common ancestor, which had already developed the most fundamental cellular processes, but there is no scientific consensus on the relationship of the three domains of life (Archaea, Bacteria, Eukaryota) or the origin of life. Attempts to shed light on the earliest history of life generally focus on the behavior of macromolecules, particularly RNA, and the behavior of complex systems.

The emergence of oxygenic photosynthesis (around 3 billion years ago) and the subsequent emergence of an oxygen-rich, non-reducing atmosphere can be traced through the formation of banded iron deposits, and later red beds of iron oxides. This was a necessary prerequisite for the development of aerobic cellular respiration, believed to have emerged around 2 billion years ago.

In the last billion years, simple multicellular plants and animals began to appear in the oceans. Soon after the emergence of the first animals, the Cambrian explosion (a period of unrivaled and remarkable, but brief, organismal diversity documented in the fossils found at the Burgess Shale) saw the creation of all the major body plans, or phyla, of modern animals. This event is now believed to have been triggered by the development of the Hox genes. About 500 million years ago, plants and fungi colonized the land, and were soon followed by arthropods and other animals, leading to the development of land ecosystems with which we are familiar.

The evolutionary process may be exceedingly slow. Fossil evidence indicates that the diversity and complexity of modern life has developed over much of the history of the earth. Geological evidence indicates that the Earth is approximately 4.6 billion years old. Studies on guppies by David Reznick at the University of California, Riverside, however, have shown that the rate of evolution through natural selection can proceed 10 thousand to 10 million times faster than what is indicated in the fossil record. Such comparative studies however are invariably biased by disparities in the time scales over which evolutionary change is measured in the laboratory, field experiments, and the fossil record.

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